Comparison of Hydraulic Fracturing Fluids Composition withProduced Formation Water following Fracturing –Implications for Fate and TransportpDebby McElreathOklahoma City OklahomaOklahoma City,OklahomaPresentation OutlineIntroductionPredicted Fate and Transport of HydraulicFracture ChemicalsF t E l tiC i f P di t dFateEvaluation-Comparisonsof PredictedConcentrations with Measured Concentrations ofIndicator ParametersTransport Evaluation – Selected RadionuclidesConclusions2Chesapeake Energy Operating Areas3Presentation OutlineIntroductionPredicted Fate and Transport of HydraulicFracture ChemicalsF t E l tiC i f P di t dFateEvaluation-Comparisonsof PredictedConcentrations with Measured Concentrations ofIndicator ParametersTransport Evaluation – Selected RadionuclidesConclusions4Predicted Downhole Fate for HydraulicFracturing Fluid ComponentsHF Fluid Component Predicted Downhole FateAcidReactswith mineralstocreatesalts,waterandCO2c deactst e a s to c eate sa ts, ate a d COCorrosion InhibitorBonds with pipe surfaces, broken downby micro-organisms or returned inproduced formation waterIron Control Reacts with minerals to create salts, water and CO2Broken down by micro-organismsor small amount returned in formation producedAnti-Bacterial AgentwaterScale Inhibitor Attaches to the formation; majority returns with produced formation waterFriction ReducerRemains in formation; broken down by micro-organisms or small amount returnedin formation produced waterSurfactant Returned with produced formation water or produced natural gasGelling Agent Broken down by breaker andreturns with produced formation waterBreakerReacts with “gel” and “crosslinker” toform ammonia and sulfate salts which arereturned in produced formation waterCrosslinkerCombines with the “breaker” in the formationto create salts thatare returned inproduced formation water5Fate and Transport of Components inFracturing FluidsElevated temperatures and pressure aswell as the interactions within thefluid itself changes the form of most componentsReactions between hydraulic fracturing fluid components and/or theformation produce constituents which can be measured as surrogates, e.g.salts, sulfates, nitrogen compounds, etc., using accepted analyticalmethodsSalts can be measured as Total Dissolved SolidsSulfatesNitrogenous compounds – Total Kjeldahl Nitrogen and Ammonia used as surrogateOften can not measure for the chemical itself, can only measure theindividual piecesKCl – can not easily measure KCl but instead measure Potassium and ChlorideSodium Hydroxide – measure Sodium as an indicator6The matrix of fracturing fluids are products rather than typicalenvironmental samples, therefore holding times, etc. are not validPresentation OutlineIntroductionPredicted Fate and Transport of HydraulicFracture ChemicalsFate Evaluation-Comparisons of PredictedConcentrations with Measured Concentrations ofIndicator ParametersTransport Evaluation – Selected RadionuclidesConclusions7Data EvaluatedVendor supplied information regarding quantity of hydraulic fracturefluids usedMixed hydraulic fracturing fluidsP d d f ti t ft h d li f t i g ti itiProduced formationwaterafterhydraulicfracturingactivitiesIterative samples over timeAnalytical results available for the followingparameters:gpVolatile organics, including glycolsSemi-volatile organicsMetals total and dissolvedMetals,total and dissolvedGeneral chemistryRadiochemistry (gross alpha/beta, Radium 226/228, and some additionalisotopic nuclides by gamma spectroscopy)8Produced Formation Water ProductionVolumes – Location 1 (Western U.S.)Comparison of Typical Annual Produced Water Volume: First year after Completion(Days 1-10 & 11-365) and Subsequent Years of Production

l ume (gal) Increasing Vo9Hydraulic Fracture Fluid Components usedin Location 1 – Western U.S.Acid –hydrochloric acidCorrosion and Scale Inhibitors –alcohols, organic acid and polymer,sodium saltIron Control –sodium compoundBiocide –gluteraldehyde and an alcoholFriction Reducer -polymer and hydrocarbonBreaker –ammonium persulfateCrosslinker–polyol and borax10Summary of Analytical ResultsSelected Indicator CompoundsProduced Formation Water after Hydraulic Fracture (First 30 Days)Location 1-Western U.S.ParameterHydraulicConcentrationsinProducedFormationWaterfollowingHydraulicFracturingwithTime(mg/L)ParameteryFractureFluid6HoursDay1(24Hours)Day2 Day9 Day30TotalKjeldahlNitrogen41.3 523 3,770 5,200 315 257Ammonia 38.5 110 140 201 273 352Chloride 126 16,500 25,500 39,600 46,500 65,800Sulfate16291.682.128.831.68.47SulfateTotalDissolvedSolids1,500 39,300 54,100 68,300 140,000 138,000Sodium 94.9 7,260 10,800 14,700 27,100 38,100Boron 0.0785 0.075 17.5 20.6 28.8 <50Benzene <1 4.15 6.34 11 7.69 10.1l11Touene 1.44 1.01 1.04 1.43 1.30 2.45Summary of Analytical ResultsSelected Indicator CompoundsProduced Formation Water after Hydraulic Fracture (First 30 Days)Location 1-Western U.S.CalculatedConcentrationsinProducedFormationWaterfollowingHydraulicParameterCalculatedConcentrationInHydraulicFractureFluid(μg/L)HydraulicFractureFluidFracturingwithTime(μg/L)12Day2(μg/L)HourGlycols 55,000 35,800 <10,000 <10,00012Concentration of Indicator Parameters andTime after Hydraulic StimulationLocation 1 – Western U.S.100000 001000000.001000.0010000.00100000.00

)10.00100.00

n centration (mg/LSulfateTDSChlorideBarium0.101.00

Co nStrontiumBenzeneToluene0.000.010 100 200 300 400 500 600 700 800Ti f H d li S i l i (h )13TimeafterHydraulicStimulation(hours)Produced Formation Water Production VolumesLocation 2 - Eastern U.S.

a l) s ing Volume (g

Increa14Hydraulic Fracture Fluid Components usedin Location 2 - Eastern U.S.Acid –hydrochloric acidCorrosion and Scale Inhibitors –alcohol, glycol, and amideIron Control–citric acidBiocide –sodium salt, sodium hydroxide, and a bromide saltFriction Reducer –water soluble polymer (nitrogenous)Breaker –sodium and potassium saltsGel –guar gum, hydrocarbon, and polymerSfl h l l l d h d burfactant–alcohol,glycoland hydrocarbon15Summary of Analytical ResultsSelected Indicator CompoundsProduced Formation Water after Hydraulic Fracture (First 30 Days)Location 2–Eastern U SEastern U.S.HydraulicConcentrationsinProducedFormationWaterfollowingHydraulicFracturingwithTime(mg/L)ParameterFractureFluid6Hours12HoursDay5 Day10 Day30Sulfate35 386<5027 28 91 56Sulfate....TotalKjeldahlNitrogen97.2 112 104 224 150 139Ammonia 9.62 39.3 42.5 70.2 60.9 160Chloride 2,790 31,200 30,800 78,300 6,0600 81,500TotalDissolvedSolids7,700 39,400 43,200 94,300 119,000 148,000Sodium 793 7940 9570 19,500 26,200 29,100Benzene 77 64.7 129 625 797 740Toluene19862.65548331,5401,65016Toluene19862.65548331,5401,650Summary of Analytical ResultsSelected Indicator CompoundsProduced Formation Water after Hydraulic Fracture (First 5 Days)Location 2-Eastern U.S.ConcentrationsinProducedFormationWaterfollowingParameterCalculatedConcentrationinHydraulicFractureFluid(μg/L)HydraulicFractureFluidHydraulicFracturingwithTime(μg/L)12HoursDay5Glycols 6,000 1,080,000 17,100 29,7002Butoxyethanol117 000<10 000<10 000<10 000‐Butoxyethanol117,000<10,000<10,000<10,00017Concentration of Indicator Parameters andTime after Hydraulic StimulationLocation 2 – Eastern U.S.1000001000000100010000

(mg/L)Barium10100

ConcentrationSodiumTDSChlorideBenzeneT l0.11Toluene0.010 100 200 300 400 500 600 700 800Time After Hydraulic Stimulation (Hours)18Presentation OutlineIntroductionPredicted Fate and Transport of HydraulicFracture ChemicalsFate Evaluation - Comparisons of PredictedConcentrations with Measured Concentrations ofIndicator ParametersTransport Evaluation – Selected RadionuclidesConclusions19Transport of Radionuclides inProduced Formation WaterPresence of radionuclides in shale formation water is well documentedAnalytical method of choice: EPA Method 901 1 modified (GammaAnalytical method of choice: EPA Method 901.1 modified (GammaSpectroscopy)Less influenced by matrix interferencesData must be reported with activity, accompanied by standard deviation andminimum detectable concentration (“MDC”)Example: 970±130 pCi/L (MDC 30 pCi/L) Radium-226Focus should be on Radium-226 and Radium-228Radium 226 and radium 228 represent more than 80% of the potentialradiation dose in ingested water20Selected Total Radionuclide Data for ProducedFormation WaterWestern U.S.Parameter Methods Units Minimum Maximum MeanError(±1 SD) MDCRadioChemistryGross AlphaSW 9310 MOD; EPA900.0pCi/L620 4,000 1,750 ±1,261 2,000Gross BetaSW 9310 MOD; EPA900.0pCi/L250 1,200 760 ±392 310Radium 226EPA 901.1 Mod.pCi/L167 904 616 ±285 79Radium 228EPA 901.1 Mod.pCi/L101 459 329 ±139 39Uranium 238EPA 901 1 ModpCi/LNot Detected580Uranium238EPA901.1Mod.NotDetectedTotal DissolvedSolidsmg/L125,000 140,000 132,500 ±10,600 NAMDC – Minimum Detectable Concentration21Selected Radionuclides andTime After Hydraulic StimulationLocation 1–Western U.S.100000100000010000

o n (mg/L) 

# Activity ( p1001000

TDS Concentrati o 

# Ci/L)10TDSRadium 226Radium 22810 100 200 300 400 500 600 700 800Time after Hydraulic Stimulation (hours)22Selected Total Radionuclide Data for ProducedFormation WaterEastern U.S.Parameter Methods Units Minimum Maximum MeanError(± 1 SD) MDCRadioChemistryGross AlphaSW 9310 MOD; EPA900.0pCi/L 4,100 6,600 5,350 ±1,767 2,700Gross BetaSW 9310 MOD; EPA900.0pCi/L ND 2,400 --- ±1,131 2,100Lead 210EPA 901.1 Mod.pCi/LNot Detected310Radium 226EPA 901.1 Mod.pCi/L 867 1,050 959 ±129 38Radium 228EPA 901.1 Mod.pCi/L 584 620 602 ±25 52Uranium 238EPA 901.1 Mod.pCi/L Not Detected 400Total Dissolved Solids Mg/L 148,000 153,000 150,500 ±3,536 NA23MDC – Minimum Detectable ConcentrationSelected Radionuclides andTime After Hydraulic StimulationLocation 2 – Eastern U.S.100000100000010000

o n (mg/L) 

# Activity (pCi /1001000

TDS Concentrati o 

# L)10Radium 226TDS22810 100 200 300 400 500 600 700 800Time After Hydraulic Stimulation (Hours)Radium24Presentation OutlineIntroductionPredicted Fate and Transport of HydraulicFracture ChemicalsFate Evaluation - Comparisons of PredictedConcentrations with Measured Concentrations ofIndicator ParametersTransport Evaluation – Selected RadionuclidesConclusions25ConclusionsProduced formation waters are highlyvariable within and between shaleformationsThe elevated temperature and pressureeffects the fate and transport ofhydraulic fracturing fluid componentsThe concentration of components inproduced formation water is related toproduced water volumes26ConclusionsMost reliable sentinel compounds are TDS,chloride and divalent cations because they are inthe highest concentrations in produced formationwaterThe concentration of TDS is predictive of thet ti f th th iconcentrationof theotherspeciesThe concentrations of potential indicatorparameters in produced formation water areovershadowed by the naturally-occurringconcentrations of these parameters in formationwatersThe presence of NORM is delayed and associatedwith higher percentages of produced formationwater with time27